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Poorly insulated attics allow expensive heated or cooled air to escape your home, wasting both money and energy. By adding insulation to your attic, you'll not only reduce your monthly utility bills, but also enjoy improved energy efficiency and greater comfort throughout the year. By reducing energy consumption, attic insulation also protects the environment from pollution and greenhouse gas emissions. Best of all, insulation is relatively easy to install, and the average attic can be completed over the course of a weekend. When the time comes to sell your home, a well-insulated attic is a plus.

Calculate Insulation Needs

1

Measure how much insulation you already have. Check the depth using a tape measure.

2

Multiply the number of inches of insulation by the R-value per inch. According to the U.S. Department of Energy, fibgerglass batts have an R-value of 3.2 per inch, while loose fill fiberglass measure R-2.5 per inch. Rockwool offers R-2.8, while cellulose made from old newspaper measures R-3.7 per inch.

3

Calculate how much insulation you need to add based on the recommended R-values for your area. Refer to the U.S. Department of Energy link in the Resources section to find recommended R-values for attics in your area. For most of California, for instance, the recommended attic insulation ranges from R-30 to R-60.

Install Fiberglass Batts Over Existing Batt Insulation

1

Put on goggles and gloves to protect yourself while handling fiberglass insulation.

2

Cut fiberglass batts by scoring them with a utility knife. Size each piece to fit snugly between the floor joists in your attic.

3

Place the batts into the space between the joists, making sure not to compress the material together. Add additional layers as needed to achieve the desired R-value.

Add Loose Fill Insulation to Existing Loose Fill

1

Rent a loose-fill insulation blower from a home improvement or hardware store.

2

Block all vents in the attic floor with baffles, making sure to extend the baffles at least four inches above the planned thickness of your insulation.

3

Have a friend add material to the hopper while you direct the blower or hose. Spray insulation to the corners and perimeter of the attic first, working your way into the center. Direct the blower away from the baffles and attic stairs to minimize cleanup.

4

Spread the insulation over the attic floor using a push broom or rake. Measure the thickness of the loose fill material periodically to achieve the desired thickness and R-value.

Things You Will Need

Tape measure

Safety glasses

Gloves

Insulation

Utility knife

Vent baffles

Insulation blowing machine

Broom or rake

Tips

Use unfaced batts only to avoid moisture problems.

If the space between your joists is already full of insulation, add new insulation on top of the joists, running the new material perpendicular to the existing batts.

Warnings

Never block attic vents or other exhaust systems with insulation.

Only walk on the floor joists in your attic, not in the spaces between. These sections won't support your weight, and you could injure yourself and damage your home.

About the Author

Emily Beach works in the commercial construction industry in Maryland. She received her LEED accreditation from the U.S. Green Building Council in 2008 and is in the process of working towards an Architectural Hardware Consultant certification from the Door and Hardware Institute. She received a bachelor's degree in economics and management from Goucher College in Towson, Maryland.